B10) PSEUDOCERATITES OF THE CRETACEOUS. 
ROEMEROCERAS Hyatt. 
These shells were so similar to the type of Buchiceras in external aspect 
that I formerly supposed the type of this genus to be an older stage of B. 
bilobatum, but more prolonged acquaintance with these forms shows that 
they are not in the same generic group. While the bifurcated costz, the 
large nodes on the umbilical shoulders, and the nodes on the ventro-lateral 
angles are the same, the involution is greater, the lateral zones more com- 
pressed and broader, the umbilici narrower, the young have larger nodes, 
and the keel entirely disappears in the full-grown shells, except perhaps in 
R. gabbi. he sutures are also quite distinct, and similar to those of Tisso- 
tidee in some species, but the first lateral saddles tend to develop three arms 
in some species and the bases of the other saddles are apt to be dentated 
more or less completely. The ventral lobes are similar to those of Buchi- 
ceras and entirely distinct from the broad ventrals of the Tissotiide. The 
same characters appear to unite K™nemiceras with Roemeroceras, but the 
development and full-grown shell in Anemiceras, especially the invariable 
presence of the concave venter, seemed to place it in closer association with 
the Pulchelliidee. 
RoEMEROCERAS GABBI n. sp. Hyatt. 
Pl. II, figs. 1-3. 
Ammonites bilobatus Gabb, 1877, Jour. ANea Nat. Sci. Pe Pa 2d ser., Vol. 
VIII, p. 270, pl. 38, fig. 3. 
In my revision of this form I made too great allowance for the possible 
variations due to age, and misled Professor Gabb in identifying this fossil 
with Buchiceras bilobatum. As compared with B. bilobatum, the nodes on the 
umbilical shoulders are much less prominent and more numerous and more 
closely approximated, the venter has large ridges not present in bilobatum, 
and the flatness and proportions of the saddles are too distinct to occur in 
the same species, even though allowance be made for the sutures in gabbi 
being nearly one volution older than those examined in B. bilobatum. The 
sutures of this species approximate more closely to those of R. syriaciforme 
than to those of any other species, but R. gabbi differs in the greater number 
and smaller size of the nodes and coste. Fig. 3 of Gabb’s plate shows the 
lateral aspect with an outer line of nodes lower on the sides and a simuous 
outline to the venter which does not appear in syriaciforme, and also a 
